Corrected di-el strength of gas

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "john cooper" <tesla-at-tesla-coil-dot-com> 

I posted an error for the di-electric strength of air in a previous 
response, the 0.4-0.7 for air was kV/mm.  Here's a new partial listing for 
some gasses (FWIW gases and gasses are both proper)

Air, 0.97
Argon, 0.18
Carbon Dioxide, 0.82 - 0.88
Carbon Monoxide, 1.02 - 1.05
Chlorine, 1.55
Helium, 0.15
*Hexafluoroethane, 1.82 - 2.55
Hydrogen, 0.50
Methane, 1.00 - 1.13
Nitrogen, 1.00
Neon, 0.16 - 0.25
Nitrous Oxide, 1.24
*Octafluoropropane, 2.19 - 2.47
*Sulfur Hexafluoride, 2.50 - 2.63
Tetrachloromethane, 6.21 - 6.33

*used in industry and research as di-electrics

The di-el strength of a gas is measured as a comparison to Nitrogen - 1.0
It was surprising for me to realize that air, which doesn't provide much 
quenching, is rated at 0.97; while Nitrogen, which quenches quite well, is 
rated at 1.00  Not much of a difference in rating for a huge difference in 
quenching ability.
Neon & Helium could be an interesting alternatives to Argon for inducing 
long streamer length although neon is more expensive than helium.  Someone 
asked about CO2, they'd be better off with compressed air.